At high edgewise flow speeds, reversed flow causes excursions in pitching moment and blade torsion on the rotor blades of helicopters and wind turbines. Our prior work has shown that a yawed fixed wing at angle of attack in reversed flow generates a sharp-edge vortex. The sharp-edge vortex is a primary feature of the flow under the rotor blade. During operation as a rotor blade at high advance ratio in a wind tunnel, stereo PIV results show that the well-formed sharp-edge vortex at 240 degrees azimuth resembles that on a forward-swept wing. This vortex stops growing before 270 degrees and convects with the blade by 300 degrees. Static pressure computed from interpolated velocity data show the effects of vortex-induced radial pressure gradient. This explains the finding of inboard-directed radial flow at 300 degrees azimuth, overcoming centrifugal effects. Viscous stress is shown to have only a minor effect on the static pressure field computation.

This content is only available via PDF.
You do not currently have access to this content.